retrieveThreadChannelById
Retrieves a thread belonging to this guild, by ID.
The cached threads are checked first, and then a request is made.
The RestAction may throw InvalidChannelTypeException if a channel with the ID was found, but isn't a thread. It may also throw ParentGuildMismatchException if the channel isn't from the same guild.
See also
Retrieves a thread from any guild, by ID.
The cached threads are checked first, and then a request is made.
The RestAction may throw InvalidChannelTypeException if a channel with the ID was found, but isn't a thread. If the thread is not owned by the current shard, GuildNotFoundException is thrown.